Arrrangement for using bioactive or osteoinductive material to build up a bone-based lateral support for implants in the jaw bone

ABSTRACT

With the aid of bioactive or osteoinductive substances ( 10 ), a bone-based lateral support is built up for an implant ( 6 ) arranged in an assigned jaw bone hole in jaw bone ( 2 ) which extends defectively or irregularly. The implant is arranged so that it can be completely or partially covered by soft tissue, and possibly periosteum, or by a unit applied to the jaw bone and/or the implant. One or more spaces can in this way be formed on the lateral surface of the implant. Body fluid penetrates from or via the jaw bone and optionally the periosteum into the respective space. The osteoinductive or bioactive substances consist of matrix molecules, growth factors and differentiation factors and/or peptides with growth-stimulating properties, all called GSS, arranged in or the implant. Body fluid with cells is secreted and said GSS is released during an incorporation stage and forms, by interaction, new bone for said bone-based lateral support. A greater freedom of choice is thus made possible for the implant in defective or irregularly extending jaw bones, without compromising the stability or esthetic appearance of the implant.

The present invention relates to an arrangement for using bioactive orosteoinductive material to build up a bone-based lateral support for oneor more implants arranged in assigned jaw bone holes. The invention ispreferably used in conjunction with defectively or irregularly extendingjaw bone, where the soft tissue of the jaw bone, sometimes combined witha separate unit, for example a polymeric and preferably stiff membrane,can be completely or partially drawn over the implant. In a completelyor partially covering position for the implant or implants, the latterform one or more spaces together with the upper or side surfaces of thejaw bone and the soft tissue with or without periosteum (its underside)and/or the unit, and body fluids pass in from or via the periosteum andsaid jaw bone surface or jaw bone surfaces to said space or spaces.

The use of implants in jaw bone holes for supporting various dentalfixtures is already known. Viewed in the horizontal plane of the jawbone, the hole/implant is normally placed near the center line. Atdefects or irregularities in the jaw bone, the implant has to be offseteither in the lateral direction or along the arc of the jaw bone so thatthe implant is given a position where, in its assigned jaw bone hole, itis surrounded by stable bone or stable bone formation. It is also knownto insert two or more implants along the arc of the jaw bone and to usethe implants as supports for a bridge construction or the like. Inconnection with the known implant, it is also already known to generallyuse bone substitute for the purpose of building bone mass around theimplant when it has been screwed into the jaw bone hole. Examples ofbone substitute which may be mentioned are autologous bone, allogenicbone, xenografts and/or synthetic preparations.

In the patent applications SE 9901972-1 and SE 9901973-9 previouslysubmitted by the same Applicant and by the same inventor as in thepresent application, it is proposed that osteoinductive material beapplied to the implant, for example on an outer surface with an outerporous oxide layer, or an outer thread which can be provided with porousoxide layer, and the implant can be self-tapping or is screwed into athreaded hole. The bioactive or osteoinductive materials can be appliedin one or more layers and released material can cooperate with bodyfluid which occurs in the layer or the narrow gap between the jaw boneand the implant. Reference may also be made to the article published by,inter alia, the inventor of the present patent application and entitled“Properties of a New Porous Oxide Surface on Titanium Implants, Volume1: The Oxidized Titanium Surface, Applied Osseointegration Research”. Itis also known to adapt the diameter of the jaw bone hole to the diameterof the implant as a function of the quality of the jaw bone. It is alsoknown to use, in connection with the implant, angled spacers which areintended to compensate for positional changes and inclinations of theimplant. The implant can consist of titanium or another biocompatiblematerial.

There is a need to be able to create a bone structure which allows theimplant to be placed more ideally in conjunction with the arc of the jawbone and so that the jaw bone, for example at said defects orirregularities, can permit implant applications where these are notinitially surrounded by the hole wall or have a relatively great degreeof exposure. There is a need to be able to adapt the implant positionsto certain surfaces or outer thread parts which are more exposed in thecircumferential and/or longitudinal direction(s) than other surfaces orouter thread parts in an initial stage. Despite the ideal application,the stability of the implant ought to be comparable to the case wherethe implant is laterally offset or longitudinally offset to a positionwhere it is completely surrounded by the wall of the hole in the jawbone.

The object of the present invention is to solve these problems amongothers and to realize implant structures which permit, from the point ofview of their appearance, a considerable improvement compared to thecase where the implant is offset laterally and/or longitudinally.

There is also a need to prevent the situation where the space formed bythe soft tissue and possible periosteum, jaw bone and implant collapsesand is filled with soft tissue, for example on account of stressesduring the incorporation process. In some cases it may be important toavoid excessively large doses of osteoinductive material in connectionwith narrow gaps between the implant and the wall of the hole in the jawbone. Such high doses may, in an initial stage, have an effect whichcounteracts the process of new bone formation. It is also important tobe able to stimulate new bone formation with the aid of the geometry ofthe spaces used for growth. The space in the jaw bone and the unit musttherefore be able to be chosen with a geometry which permits effectivenew bone formation. The invention solves these problems too.

There is a need for surgeons and other treating personnel to have agreater freedom of choice in positioning the implants more independentlyof the jaw bone status than previously, but without the stability of theincorporated implant being compromised. The invention solves thisproblem too.

The feature which can principally be regarded as characterizing anarrangement according to the invention is that the bioactive orosteoinductive material consists of growth-stimulating substance orsubstances (here called GSS), arranged in or on the implant, preferablyon one or more outer side surfaces or one or more outer thread partswhich in an initial stage are exposed from the jaw bone. Said GSS, in astage of incorporation following the initial stage, passes into eachclosed space and interacts with the aforementioned cells, for examplethe stem cells, thus forming the bone-based lateral support for theimplant. Different types of GSS can be used, and examples of GSS whichmay be mentioned are matrix proteins, growth factors and differentiationfactors and/or peptides with growth-stimulating properties.

In one embodiment, the invention is used for an implant with a positionfor the jaw bone's imagined horizontal plane which is offset in relationto the center line of the jaw bone in the horizontal plane so that theimplant in said initial stage has first side surface parts or outerthread parts having a greater degree of exposure than other side surfaceparts or outer thread parts. The bone-based new formation is intended,in the stage of incorporation, to give the first side surface parts orouter thread parts an increased degree of bone coverage or increaseddegrees of bone coverage. In one embodiment, two or more implants can bearranged along the horizontal extent of the jaw bone in assigned jawbone holes. Said implants are in this case arranged at defects orirregularities in depth and/or the lateral direction or lateraldirections. In the stage of incorporation, the jaw bone's defects orirregularities are substantially filled and the implant is givensubstantially the same degree of coverage with bone all round it afterthe stage of incorporation has been completed. In the case of a jaw bonestrongly degenerated in the vertical direction, all the implants in oneembodiment can be given bone-based lateral supports extendingsubstantially identically in the height direction.

In one embodiment, first portions of each implant have a greater degreeof exposure than other portions of the implant or implants. Said firstportions are in this case coated with more GSS than the other portions.The aforementioned unit made of, for example, stiff and/or polymericmembrane can be used temporarily or can be included permanently in thefixed installation. The unit can be attached to the jaw bone and/or theimplant, for example by screw(s), during at least the initial stage andthe stage of incorporation. The unit can have an internally curvedsurface which, when the unit is in the applied position, is directedtoward the side surface or outer thread of the respective implant. Theunit can be designed with an upper part which extends completely orpartially over the upper or outer surface of the implant. The respectiveouter surface or outer thread exposed in the initial stage extendsbetween 20-180°, preferably 30-120°, viewed in the circumferentialdirection of the implant. Said outer surface exposed in the initialstage can also extend 20-80%, preferably 30-70%, along the heightdirection of the implant.

Further embodiments are set out in the attached dependent claims.

By means of what has been proposed above, it is possible to achieveoptimum implant positions, especially from the point of view ofappearance, in defective or irregular jaw bones, without the stabilityof the implant being compromised. Known and well established materialscan be used for the implant, for example titanium, ceramic, etc. Theinvention functions for one or more implants, and in the case of severalimplants these can be arranged one after another along the horizontalextent of the defective or irregular jaw bone. The invention functionsfor portions exposed to greater or lesser extents in the initial stage.A separate unit or the stiff and/or polymeric membrane can be used tosecure the actual space in which the new formation of dentine takesplace by means of GSS. The unit/the membrane can be used temporarily oras a continuous/permanent fixture. The unit/membrane can be secured bymeans of screws, with arms or structured parts, etc., and made oftitanium, plastic, etc.

A presently proposed embodiment of an arrangement having the featurescharacteristic of the invention will be described below with referenceto the attached drawings, where

FIG. 1 shows, in horizontal section, a lower jaw bone with a defect orirregularity, in or on which an implant is to be anchored, said figurealso showing positions for the implant which have been indicated in theprior art,

FIG. 2 shows, in vertical section, an implant fitted in a jaw bone hole(in the upper jaw) and where a space for a lateral support formed by newbone is included in the implant's anchoring,

FIG. 3 shows, in vertical section, an implant fitted in a lower jaw,said lower jaw having a defect or irregularity different than the defector irregularity in FIG. 2,

FIG. 4 shows, in horizontal section, the use of a unit applied to thedentine, for example a membrane made of titanium, or plastic, etc., and

FIG. 5 shows, in a side view, the extent of the unit.

In FIG. 1, a lower jaw bone is shown diagrammatically by 1. The lowerjaw bone itself is indicated by 2, and the soft tissue of the jaw bone,with underlying periosteum, is shown by 3. Generally speaking,periosteum may be completely or partially absent, but in the presentcase it is assumed to be present, although not specifically pointed out.The arc-shaped extent of the jaw bone in the horizontal direction isshown by 4. The jaw bone is provided with a defect or an irregularitywhich is indicated by 5. When fitting implants optimally in a jaw bonehole in the jaw bone, it may be necessary from the point of view ofappearance, the point of view of installation, etc., to place theimplant at the irregularity or defect 5. In the previously knowntechnique, this freedom of positioning has not been possible and it hasoften been necessary to fit the implant in a position which is offset inrelation to the defect or irregularity and where more bone mass for theimplant and the jaw bone hole has been available. Alternatively, it hasbeen necessary to fill the space around the implant with bone substituteof various types. In FIG. 1, an implant 6 is optimally fitted at thedefect or irregularity 5. Said previous laterally offset positions havebeen indicated by 7 and 8, and it will be seen that the implant position7 has to be offset in relation to implant position 6 by a distance A forsufficient bone mass to be present at the partially shown jaw bone hole2 a and the implant 7 arranged therein. In an alternative offset to theposition 8 and jaw bone hole 2 b, the implant 6 has to be offset by adistance B. It will be appreciated that such offsets can affect theimplant fixture from the point of view of appearance and that measuresmay be required in the actual dental fixture, which can include spacersleeves, bridge construction, etc. When replacing a lost tooth in anotherwise intact row of teeth, it will also be appreciated that problemsmay arise when applying the implant for the lost tooth if a defect orirregularity is present in the jaw bone at the location of the losttooth.

In accordance with the invention, the implant 6 is placed at the defector irregularity 5 and the positions 7 and 8 are therefore not used. Inaccordance with the invention, a space 9 is created on the exposed sidesurface 6 a. The angle for the exposed side surface is indicated by a inFIG. 1. In a preferred embodiment, the size of said angle can assumevalues of between 20 and 180°, preferably values in the range of30-120°, viewed in the circumferential direction (i.e. in the plane inFIG. 1). The implant is provided with layers 10, 11 of GSS. In apreferred embodiment, the concentration of GSS in the layer on theexposed side surface or outer thread part 6 a is greater than the layer11 which is directed toward the jaw bone 2. It is thus possible to workwith a predetermined angle position of the implant when it has beenscrewed or secured in position in the jaw bone/jaw bone hole 2 c. Forreasons of clarity, the concentration of GSS in said layers 10, 11 issymbolized by an unproportional thickness in FIG. 1. In the illustrativeembodiment according to FIG. 1, a soft tissue and periosteum part 3 a isdrawn across the surface Ga exposed in relation to the jaw bone 2. Bodyfluid accumulates in a manner known per se in the space 9, this bodyfluid being secreted from or via body tissue, the jaw bone 2 and thesoft tissue and periosteum 3, 3 a. In a likewise known manner, this bodyfluid contains cells, and here reference may be made to the fact thatthe periosteum in particular supplies a large amount of stem cells. Saidbody fluid is symbolized in FIG. 1 by arrows 12 and 13. Said body fluidreleases said GSS from the surface 6 a of the implant and, through saidsecretion and release, a process or interaction is initiated for newformation of bone in the space 9. Thus, during a stage of incorporationof the implant 6, a lateral support is formed in the space 9, thislateral support consisting of newly formed bone, giving the lateralsupport a character corresponding to the compact bone mass, cf. thepositions 7 and 8 for the implant. The defect or irregularity 5 isfilled by the new bone formation. The process of release of GSS issymbolized by arrows 14 in the figure. In the nonexposed portions 6 b ofthe implant, a process of new formation of bone takes place in acorresponding manner in a gap 15 between the side surface 6 b of theimplant and the wall of the hole 2 c. In this case, the body fluidformed from the jaw bone is indicated by 16, and the release of GSS onthe surface 6 b is indicated by arrows 17. The layer 11 must not obtaina dose resulting in excessive reaction of GSS on the dentine 2, as thismay in some cases involve a degeneration process of the bone formation.The implant can be used in accordance with said patent applications fromthe same Applicant and inventor. Thus, the outer surface in question,for example a threaded outer surface, can be arranged with an oxidelayer having pores in which GSS is stored. In one embodiment, GSS can beused in combination with material containing calcium phosphate. In oneembodiment, bone substitute known per se and available on the market canbe used in combination with said GSS. In this connection, reference maybe made to autologous bone, allogenic bone, xenografts and/or syntheticmaterials or substances.

In FIG. 2, corresponding parts and arrows have been indicated with thesame reference numbers. The height of the exposed part 6 a has beenindicated by H, and the inner parts of the implant are surrounded by jawbone 2. The implant's parts surrounded by jaw bone have been indicatedby H′. The value of H can be 20-80% of the total height of the implant,which is symbolized in FIG. 2 by H″. The preference is for values in therage of 30-70%. The implant can be provided with a thread 6 c in amanner well known per se.

FIG. 3 shows an implant 6 a′ arranged in a lower jaw bone. Parts in FIG.3 corresponding to FIGS. 1 and 2 have been indicated in FIG. 3 with thesame reference numbers with addition of a prime marker. As can be seenfrom FIG. 3, the defect or irregularity has another course which exposesouter surfaces or outer thread parts of the implant, different from thecase according to FIG. 2. In this case, the soft tissue together withpossible periosteum 3 a′ has also been drawn across the upper parts 6 dof the implant 6 a′. The release and secretion functions correspond tothose described above.

In accordance with FIGS. 4 and 5, a temporary or permanent unit 19 canbe used to create the space 9″. In some cases the unit can be secured inthe jaw bone 2′ by means of screws 20 and 21 or other securing means.The unit can consist of a polymeric or metal-based, stiff membrane and,like the implant, can be made of titanium, and in one embodiment it hasan arcuate or semicircular inner surface 19 a. Said inner surface can beprovided with said material GSS. A release function of GSS can takeplace in cooperation with said body fluid secretion 16″ according to theabove. The function of secretion from the unit 19 is symbolized by 23 inFIG. 4. The unit 19 can be provided with an upper part 19 b which canextend in across the implant, i.e. across the top faces of the implant.The upper part 19 b can also be provided on its top face with layers ofGSS. The arcuate shape 19 a has advantages for the growth function whichis especially advantageous in the case of convex surfaces correspondingto the surface 19 a. The coating of GSS 22 can also be combined withbone substitute in accordance with what has been described above inrelation to the space 9, 9′.

The arc line 4 constitutes the ideal arc line, while the actual centerline extending crookedly in a jaw bone with defects or irregularities isnot shown in detail. This center line is referred to as the actualcenter in the horizontal plane. The upper or outer surface of theimplant is indicated by 6 d′ in FIG. 3.

The invention is not limited to the embodiment shown above by way ofexample, and instead it can be modified within the scope of the attachedpatent claims and the inventive concept.

Reference may be made here to patent applications submitted to theSwedish patent office on the same day as the present patent applicationand by the same Applicant and inventor. Said applications have thefollowing titles:

-   -   a) “Arrangement for using osteoinductive or bioactive material        to induce bone and/or increase the stability of implants in the        jaw bone, and an implant intended for this purpose”.    -   b) “Arrangement for implants bearing growth-stimulating        substance or substances, and one such implant”.    -   c) “Arrangement of two or more implants provided with        growth-stimulating substance(s)”.    -   d) “Arrangement for increasing the stress resistance of        implants, and one such implant”.

1. An arrangement for using bioactive or osteoinductive material tobuild up a bone-based lateral support (18,18′) for at least one implant(6) arranged in an assigned jaw bone hole (2 c) and where the implant isarranged so that it can be completely or partially covered by softtissue, with or without the periosteum of the jaw bone, or by a unitapplied to the jaw bone, and where the implant, when completely orpartially covered, forms one or more spaces together with the softtissue and the possible periosteum and/or the unit and the upper orlateral surface(s) of the jaw bone in question, and cell-containing bodyfluid penetrates into this space or these spaces from at least said jawbone, characterized in that the bioactive or osteoinductive materialcomprises GSS comprising matrix molecules, growth factors anddifferentiation factors and/or peptides with growth-stimulatingproperties, arranged in or on the implant, which GSS, in a stage ofincorporation following the initial stage, passes into each closed spaceand interacts or integrates with said cells and thus forms thebone-based lateral support for the implant.
 2. The arrangement asclaimed in patent claim 1, characterized in that the jaw bone hole (2 c)and thus the implant (6) have a position which is offset in relation tothe real center line of the jaw bone in the horizontal plane, so thatthe implant in said initial stage has first side surface parts or outerthread parts which have a greater degree of exposure than other sidesurface parts or outer thread parts, and after the stage ofincorporation the bone-based lateral support is intended to give thefirst side surface parts or outer thread parts an increased degree ofbone coverage or increased degrees of bone coverage.
 3. The arrangementas claimed in patent claim 1, characterized in that two or more implantswhich are arranged along the horizontal extent of the jaw bone inassigned jaw bone holes are arranged in conjunction with defects orirregularities in depth and/or the lateral direction(s), and in that, inthe stage of incorporation, they substantially fill the jaw bone defectsand irregularities and give the implant substantially the same degree ofrecessing after the stage of incorporation.
 4. The arrangement asclaimed in patent claim 1, characterized in that, in the case of a jawbone greatly degenerated in the vertical direction, all the implants aregiven bone-based lateral supports extending substantially identically inthe vertical direction.
 5. The arrangement as claimed in patent claim 1,characterized in that, first portions (6 a) of each implant with agreater degree of exposure than other portions (6 b) of the implant orimplants are covered with GSS with a greater or lesser degree ofconcentration of GSS than the other portions.
 6. The arrangement asclaimed in claim 1, characterized in that the unit (19) can betemporarily or permanently attached to the jaw bone, the unit, whentemporarily attached, being applied during the initial and incorporationstages.
 7. The arrangement as claimed in patent claim 1, characterizedin that the unit has an internally curved surface (19 a) which, when theunit is applied, is directed toward the side surface (6 a) or outerthread part of the respective implant (6).
 8. The arrangement as claimedin patent claim 1, characterized in that the unit has an upper part (19b) which completely or partially extends over the implant's upper orother surface (6 d′).
 9. The arrangement as claimed in claim 1,characterized in that, at its surface covered by the wall of the jawhole (2 c), the implant works with body fluid accumulation in the layeror the gap (15) between the implant and the wall (2 c).
 10. Thearrangement as claimed in claim 1, characterized in that the implant'souter surface (6 a) exposed in the initial stage extends between20-180°, viewed in the circumferential direction of the implant.
 11. Thearrangement as claimed in claim 1, characterized in that the implant'souter surface exposed in the initial stage extends 20-180%, viewed inthe height direction (H).
 12. The arrangement as claimed in patent claim1, characterized in that the unit is coated with GSS on its outersurface (6 a) exposed toward the implant in the initial stage.
 13. Thearrangement as claimed in claim 1, characterized in that the implant'souter surface (6 a) exposed in the initial stage extends between30-120°, viewed in the circumferential direction of the implant.
 14. Thearrangement as claimed in claim 1, characterized in that the implant'souter surface exposed in the initial stage extends 30-70%, viewed in theheight direction (H).
 15. The arrangement as claimed in patent claim 2,characterized in that two or more implants which are arranged along thehorizontal extent of the jaw bone in assigned jaw bone holes arearranged in conjunction with defects or irregularities in depth and/orthe lateral direction(s), and in that, in the stage of incorporation,they substantially fill the jaw bone defects and irregularities and givethe implant substantially the same degree of recessing after the stageof incorporation.
 16. The arrangement as claimed in patent claim 2,characterized in that, in the case of a jaw bone greatly degenerated inthe vertical direction, all the implants are given bone-based lateralsupports extending substantially identically in the vertical direction.17. The arrangement as claimed in patent claim 3, characterized in that,in the case of a jaw bone greatly degenerated in the vertical direction,all the implants are given bone-based lateral supports extendingsubstantially identically in the vertical direction.
 18. The arrangementas claimed in patent claim 2, characterized in that first portions (6 a)of each implant with a greater degree of exposure than other portions (6b) of the implant or implants are covered with GSS with a greater orlesser degree of concentration of GSS than the other portions.
 19. Thearrangement as claimed in patent claim 3, characterized in that firstportions (6 a) of each implant with a greater degree of exposure thanother portions (6 b) of the implant or implants are covered with GSSwith a greater or lesser degree of concentration of GSS than the otherportions.
 20. The arrangement as claimed in patent claim 4,characterized in that first portions (6 a) of each implant with agreater degree of exposure than other portions (6 b) of the implant orimplants are covered with GSS with a greater or lesser degree ofconcentration of GSS than the other portions.